The objective of this study is to determine that steady state is reached for 3k-ketogestrel and ethinyl estradiol within each dosing phase, and to determine that 3k-desogestrel steady state serum levels are proportional to desogestrel dose (linear kinetics) during cycle 3 of CTR 99 treatment and that Ethinyl estradiol serum levels are similar under different co-administered desogestrel doses during Cycle 3 of CTR 99 treatment (dose equivalency)